S5, E16: The milestone 100th episode of BONES takes viewers back in time six years as Brennan and Booth recount the first case they worked on together. With Sweets finishing his book on their partnership, Brennan and Booth take this opportunity to set the record straight. A young and rebellious FBI Agent Booth seeks the help of an team of anthropological scientists and a street artist to find the evidence that will prove his high-profile suspect guilty. Although in unfamiliar territory, Dr. Brennan, her grad student Zack (guest star Eric Millegan) and Hodgins get right to work, impressing Booth with their knack for uncovering new leads and substantiating his theory about a well-connected district judge. While the case cements a foundation for a successful future partnership, it also reveals the convoluted romantic beginnings of the formidable duo – whose feelings for each other almost destroyed the team but still linger years later.